Phased Array Ultrasound Apparatus Using Polarization State Control
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Solution Overview
Problem
Phased array ultrasound apparatuses require complex and costly circuitry for independent control of multiple transducers to form desired ultrasonic wave focus points, which becomes impractical for larger arrays.
Innovation Solution
The use of piezoelectric material with two polarization states and shared control signals applied to electrodes, allowing for phase delay adjustments and polarization state changes in selected transducers to achieve desired ultrasonic wave formation with reduced electrode count and simpler circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If independent control of each transducer element is implemented, then accurate ultrasonic wave focusing is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent merges the control of multiple transducer elements by sharing control signals across adjacent elements. Specifically, control signals for row electrodes and column electrodes are shared among multiple transducer elements, reducing the total number of independent control channels from N (for N elements) to approximately 2√N (for row and column electrodes), thereby simplifying the control circuitry while maintaining focusing capability
Solution Approach 2:
The patent introduces polarization state control as a local degree of freedom for each transducer element. By individually controlling the polarization state (positive or negative) of each element's piezoelectric material, the system can locally adjust the phase of emitted ultrasonic waves, enabling accurate focusing despite shared control signals
2Adaptability or versatility
If the number of transducer elements is increased to form larger arrays, then ultrasonic wave control capability is improved, but the number of required connections and circuitry increases
Solution Approach 1:
The patent applies a two-dimensional electrode arrangement where row electrodes and column electrodes intersect to control transducer elements. This merging approach allows N transducer elements to be controlled by approximately 2√N electrodes rather than N independent connections, enabling scalable array designs without proportional increases in circuitry complexity
Solution Approach 2:
Each electrode (row and column) serves multiple transducer elements simultaneously, making the control system universal rather than element-specific. This multi-functionality allows the same electrode to control different elements at different times or in combination with other electrodes, reducing the overall number of required connections
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate control of ultrasonic waves with fewer electrodes, allowing for efficient formation of focused waves for haptic feedback and other applications while reducing the complexity and cost of the control circuitry.
Implementation Method 1
each transducer element comprises a layer of piezoelectric material between the first electrode and the second electrode configured to control a vibration of the piezoelectric material to induce emitting of an ultrasonic wave by the transducer element
Implementation Method 2
the piezoelectric material exhibits two polarization states, wherein a phase of an emitted ultrasonic wave by the transducer element differs 180° between the two polarization states of the piezoelectric material
Implementation Method 3
By focusing an ultrasonic wave in air, a focus point of sound pressure may be formed in mid-air
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~6
AI summary
A phased array ultrasound apparatus comprises an array of ultrasound transducer elements (110); a plurality of first electrodes (132) and a plurality of second electrodes (134), such that each transducer element (110) is associated with one first (132) and one second electrode (134); wherein each transducer element (110) comprises a layer (118) of piezoelectric material between the first (132) and the second electrode (134) to induce emitting of an ultrasonic wave based on control signals, wherein control signals are shared by the transducer elements (110); wherein a phase of an emitted ultrasonic wave differs 180° between two polarization states of the piezoelectric material; and wherein the phased array ultrasound apparatus (100) is configured to individually change polarization state of the piezoelectric material of selected ultrasound transducer elements (110) before activating at least a subset of the ultrasound transducer elements (110) in the array to form a combined ultrasonic wave.